Suction muffler



' Filed Feb. 14, 1940 Patented Feb. 25, 1941 2,233,327

UNITED STATES PATENT OFFICE 2,2ss,s2:1 sUorroN MUFFLER Urban Sauer, Pittsburgh, Pa, assignor of twofiiths to Harry R. Levy, McKeesport, Pa.

' Application February 14, 1940, Serial No. 318,924

17 Claims. (Cl. 181-43) This invention relates to a suction mufiier. variations and modifications may be resorted to The invention aims to provide, in a manner which fall within the scope of the invention as as hereinafter set forth, a muiller of the class claimed.

referred to for respectively creating a suction In the drawing:

in the exhaust line of the engine to facilitate Figure 1 is a longitudinal sectional view of a 5 the scavenging of the burned gases; mufiling and suction muiller in accordance with this invention, silencing the exhaust noises; eliminating back Figure 2- is a section on line 2-2, Figure 1, pressure in the exhaust line and mufiler; aid- Figure 3 is a fragmentary view in elevation ing in cooling the exhaust line side of the enlooking toward the inner end of the muflier, and

gine; aiding elimination of carbon deposits; re- Fi ure 4 is a f me t ry view in nal ducing the consumption of fuel by the elimina section of a modified form. tion of back pressure; obtaining increased power With reference to Figures 1, 2 and 3, the mufiier by the elimination of the adulteration of the inincludes a housing 4 having its leading terminus coming charges of fuel by mixing with burnt open throughout, as at 5. The housing 4 comases; increasing the acceleration of the engine prises a rear' end portion 6 of uniform diameter due to lessened resistances of gases in the exhaust formed at its leading end with an w y d line and mufiler; and materially reducing the disrected annular flange l, a apered in rmediate charge or obnoxious smoke from the tail pipe. p ti n 8 h vin a c rv d n urne ne nd The invention further aims to provide, in a p rt 9, a antially i l r" s p er manner as hereinafter set forth, a suction mufiier end p o "0 ed With an Op ng 5 i lengthwhereby a thorough mixture of air is had with Wise thereof d a Tear Wall provided with a the gases to thereby reduce the hazard of carbon forwardly d e ted annular fl e I3 which V61- monoxide gas. laps and is secured to the rear end of the rear The invention further aims to provide, in a portion P manner as hereinafter set forth, a suction muiller e flange 7 e es nto e re e d f t e whereby the hot xhau t gases h t ni intermediate portion whereby the latter is inset therethrough are'divided into very fine streams, with respe t t e P 41 0 5- The leadin e d the pressure impulses for the exhaust gases are p t 9 0f the intermediate Portion 3 merges to applied in very fine streams and which divisions the rear End Of the Said Outer end portion, divides and dissipates the sound waves carried The real portion 6 s ed w all pe 3- by the gases. The wall i2 is provided respectively with a pair The invention further aims to provide, in a of diametrically pp s t a p nings :4; manner as hereinafter set forth, a suction muffler a P 0f interiorly t e ded b 5 on its f acting to divide the sound waves of the gases Ward face forming forward continuations of the 2-) while travelling through the mufiier whereby said lls of openings it; and a s ri s of coaxially rwaves are dissipated. ranged rows it, it, l8, l9 of spaced air intake The invention further aims to provide, in a p s disposed c ially with the axis of manner as hereinafter set forth, a suction muffler Wall capable ofbeing adjusted, as well as dismantled ured to the orw r fa e f e w ll I2 are or opened to permit of cleaning it when desired. e ea s O a Set Of fOrWaPdlY ed The invention further aims to provide, in a axially arranged spaced frusto-conical members manner as hereinafter set forth, a suction muffler 2U Co d t0 form uct P ss es 2| for the purpose referred to which is simple in f spir form leading f t air intake p I its construction, strong, durable, compact, readily ings l1, l8, I9 to the forward or leading ends 4.) installed with respect to the exhaust of an inof said members. Each of said members has its ternal combustion engine, thoroughly efficient in outer periphery formed with spiral blades or its use and comparatively inexpensive to manuvanes 22. The blades on the outer peripheries facture. of the inner ones of the members 20 abut and co- Embodying the aims aforesaid and others act with the inner peripheries of the outer ones which may hereinafter appear, the invention conof the members 20 to formthe passages 2|. The 50 sists of the novel construction, combination and length of the members 20 is less than the length arrangement of parts to be more specifically reof the rear portion 6 of the housing 4. Secured ferred, to and illustrated in the accompanying at its rear or follower end to the forward face of drawing, wherein is shown embodiments of the the wall I2 is a frusto-conical member 23 of 5- invention, but it is to be understood that changes, greater diameter and length than any one of the members 29. The member 23 has its rear portion encompassing in spaced relation the outer member 29 of the set. The spiral blades or vanes 22 on the outer member 29 bear against and form in connection with the inner periphery of the member 23 air conducting passages 23 of spiral form leading from the air intake openings I8 to the forward or leading ends of the members 29. The member 23 is of less length than housing portion 8 and that portion of member 23 projecting beyond the leading ends of the members 29 provides an air receiving chamber 24 of frustoconical form provided at its leading end with a tubular air discharge member 24" of a length to extend beyond the leading end of housing portion 8. The members and 23 are to be suitably con-' nected together.

Arranged within and spaced from the inner face of the housing 4 is a series of gas ejectors disposed coaxially and arranged in endwise spaced relation. As shown by way of example the set consists of four ejectors indicated at.

25, 28, 21 and 28. The ejectors progressively increase in dimensions from the leading ejector 28 to the follower or rear ejector 25. The

ejector 25 is formed of a rear or follower hollowportion 29 and a hollow frusto-conical front or leading portion 39 of less length than the portion 29. The body of the portion 29 gradually increases in thickness from its follower to-its leading end. The inner and outer diameters of the portion 29 gradually decrease from the rear or follower end of such portion to its point of mergence with the portion 39. The said portion 29 corresponds in length to and is arranged in the housing portion 8. The said portion 39 extends into the rear part of housing portion 8. The rear or follower end of the said portion 29 is secured to the forward face of wall I2 inwardly of the bosses I5. The said portion 29 is of greater length than and encompasses in spaced relation the member 23. The said portion 39 has its outer periphery formed with spiral grooves 3| open at eachend'and which lead downward from the outer periphery of ejector 25 in a direction towards ejector 28 for ejecting the gases into the latter. The tubular discharge member 24 for the chamber 24 is arranged within the portions 29, 39 of ejector 25 and is disposed coaxially with the several ejectors.

Each of the ejectors 28, 21, 28 are of like form; each consists of a rear or follower portion 32 and a frusto-conical or tapered front or leading portion 33 of less length than the portion 32. The rear or follower end edge of the portion 32 is beveled in a manner to form a frusto-conical or tapered edge surface 34. The outer periphery of the portion 33 is formed with spiral grooves 35 providing gas conducting passages leading from the outer to the inner side of an ejector.

The edge surface 34 of ejector 26 encompasses in spaced relation the portion 39 of the ejector 25. The edge surface 34 of the ejector 21 encompasses in spaced relation the portion 33 of the ejector 28 and the edge surface 34 of the ejector 28 encompasses in spaced rel'ationthe portion 33 ot the ejector 21.

The mufller includes a nozzle 38 formed of a tubular discharge member 31 of the desired length and diameter having a frusto-conical leading end terminal portion 38 and an annular head 39 formed with tapered leading and follower end edges 49, 4| respectively. The rear terminal portion of the member 31 extends into and is secured to the head 39. The edge 4| of the head 39 encompasses in spaced relation the portion 33 of the ejector 28.

The housing portion I9 encompasses and is secured to the outer periphery of the head 39 of the nozzle 38. The leading end of housing portion I9 is arranged in close proximity to the edge 49 of head 39. I

The ejectors, other than the ejector 25, are formed on the outer peripheries of their portions 32 with a, pair of oppositely disposed diametrically opposed laterally extending lugs 42, 43 formed with inclined threaded openings 44. The lugs 42 align with each other. The lugs 43 align with each other. The lugs 42, 43 are disposed at a forward inclination with respect to the aforesaid portions 32. The openings 44 in the lugs 42 align. The openings 44 in the lugs 43 align. There is correlated with the lugs 42 a headed combined holding and adjusting rod 45 for the ejectors 28, 21 and 28. There is correlated with the lugs 43 a headed combined holding and adjusting rod 48 for the ejectors 28, 21 and 28. The rods 45, 48 correlate with the lugs 42, 43 for suspending the ejectors 28, 21, 28 in the housing portion 8 and for maintaining such ejectors in spaced relation, as well as for adjusting the space between the ejector 25 and ejector 28, between the ejectors 28, 21, 28 and between the ejector 28 and the head 39 of the nozzle 38.

The rods 45, 48 extend through the openings II of housing portion I9, through the openings 44 in the lugs 42, 43 and threadedly engages in the bosses I5 and openings I4. The heads 41 of the rods 45, 48 abut the leading side of the nunsing portion I9. The rod 45 has spaced groups of threads 48 which threadedly engage with the threads of the openings 44 of the lugs 42. The rod 48 is formed with spaced groups of threads .49 which threadedly engage with the threads of the openings 44 of the lugs 43. There is correlated with each lug 42 or 43 a pair 0! locking nuts 59 disposed on each side of a lug and threadedly engaging with. a rod 45 or 48.

The housing portion 8 in connection with the ejector 25 provides a receiving or reservoir chamber 5| for the exhaust gases and these latter are supplied to the chamber 5| by an exhaust gas conducting pipe 52 of angle-shape form which leads from the motor or engine. The pipe 52 includes a horizontal leg 53 and a vertical leg 54; the latter opens into the chamber 5| and is secured to the wall of opening I3 of housin portion 8. The housing portions 8, 9 and I9 in connection with the ejectors 28, 21, 28 and nozzle head 39 form a leading extension or continuation 55 of the chamber 5|. The leading and of continuation 55 is closed by housing portion I9. The rods 45, 48 extend through the continuation 55 and the chamber 5|.

The modified form 58 shown by Figure 3 is similar in construction to the form shown by Figure 1, with this exception that the nozzle 51 of the form 58 has connected to its leading end a tail pipe 58 consisting of a tubular member 59 integral at its follower end with the frustoconical outer part 89 of nozzle 51 and at its leading. end merging into a flared member 8| which terminates at its leading end into the follower end of a frusto-conical member 82, a frusto-conical member 83 of greater length than. surrounding in spaced relation and extending rearwardly and forwardly from member 82, a tubular member 84 merging at its follower end into the leading end of member 83 and its leading end merging into the follower end of a flared member 85 which terminates at its leading end into the follower end of a frusto-conical member 66, a irusto-conical member 61 of greater length than, surrounding in spaced relation and extending rearwardly and forwardly from member 66 and a discharge pipe 68 merging at its follower end into the leading end of member 61. The members 63 and 61 having their inner peripheries formed with spiral blades or vanes 69 which coact with the outer peripheries of the members 62, 66 to form air conducting passages 10 of spiral form leading from the atmosphere to the member 64 and to the discharge pipe 68. The members 63, 61 are suitably connected to the members 62, 66 respectively. Otherwise than that as stated the construction of the form 56 will be the same as that referred to in connection with the form shown by Figure 1.

The space between the ejectors is shown somewhat exaggerated by the drawing. The ejectors are spaced slightly apart whereby when the muiiier is used there will be practically only a clear of a sixteenth of an inch more or less between the tapered portions, adjusted to volume and pressure varied to the capacity of the engine. The tapered portion of each ejector being confined to the thickness of the body of the latter and the spirals on the tapered portion being cut in the latter, whereby there will not be on the inside of the ejectors corners or offsets to hinder the forward movement of the air and gases. The gases enter from the receiving or pressure chamber into the openings or slits formed between the tubular portion of a leading ejector-and the tapered portion of a follower ejector.

The exhaust gases enter the outer chamber at an angle, the gases stock up in the chamber 5i around the point of entry, rotate about the periphery of the ejectors, thereby causing the pressure of the gases to distribute itself evenly in case of a very light pressure the tendency of the gases would be to run through the grooves of g the first ejector, but in caseof a strong pressure the tendency of the gases would be to run to the extreme end of the extension 55 of the chamber 5i and then through the grooves of the ejectors furthest away from the point of entry, the excess of the gases would run through the grooves of the ejector second furthest away from the entry,

- and so on until the gases have divided itself, and ultimately feeds through all the grooves of all the ejector heads into the interior of the ejectors. The passage of the exhaust gases through the ejector of the series, results inadivision of the hot exhaust gases into very fine streams, with a division of the pressure iiripulses into fine streams, which division tends to divide and .dissipate the sound waves carried by the gases.

The rotation oi'the gases about each ejector results in the formation of a complete circle of gases about the electors as the gases whirl to a center in the chamber ahead of each ejector,

setting up a series of vertexes, forming pockets,

of hot gases, of lessened pressure to the rear, which fill up as avoid drawing the cold air from the air inlet leading through the grooves between the frusto-conical members, into the air chambenpast the first ejector, the mixture beil'lli drawn by the vortex created past the second ejector and so on through the course of travel of the mixture successivelyfthrough ear-2h ejector.

The sheet of the cold air drawn into the pocket of hot gases of the vortex created by action of the first ejector, causes partial expansion of the cold air, the speed of the moving mixture preventing complete expansion, whereupon the effect of the contact of the mixture with the hot gases in the vortex created by action of the. sec-,

' are prevented from passing through by reason of this packing in of gases and air, these packings taking place each time the expansion is repeated and successively sothat the echo can not pass through and out to the outside.

The mixture of hot gases and air having been well expanded after passing through the length of the ejector series and after spinning through the nozzle, creates a condition in the nozzle of greatly lightened pressure, which removes obstruction or hindrance to the drawing in of great-' er volume of cold air through the air ,inlet and into the inside of the ejector series, so that there is always a steady stream of air and gases going through, and the passageway of the gases and air is always filled, so that the echo cannot get through the usual make and break that would otherwise occur in the pressure impulses of the gases, which would otherwise allow the echo of the explosion noises to come through and pass out to the outside. I

The steadiness and constancy of flow intercepts the passage of the sound waves and per. mits a steady flow at the exit into the atmosphere.

Figure 4 shows a plurality of air inlets, in such number and in such position on the tail pipe for the purpose of effecting a further reduction in pressure of the mixture. The mixture will draw in air through the spiraled grooves on the face of the inlet walls so as to cool the mixture further and thereby reduce the pressure. The reduction in pressure will overcome the friction of the moving mixture against the walls of the tail pipe. This promotes a more rapid expulsion of the gases. exit of the tail pipe they would be well expanded, cooled and little above atmospheric pressure.

The spiraled grooves on the air inlets along the tail pipe, as well as at the inlet to the muiiler proper are deeper and wider at their leading ends, and narrower and shallower at their inner or follower ends, tapering inwardly so as to pack the air in. The force of the air being drawn in keeps the echo from backing out. The spiral grooves make a longer wall against the backing out than the straight groove would.

The cutting of the tapered spirals on the thickness of the tubing gives a free, unhampered right of way to the moving mixture. The tapering of the interior of the series of ejectors inwardly keeps the flow steady, keeps the ejector filled, and. causes an increased velocity of the mixture to take the gases away, rather than to permit undue expansion at that point.

The construction and operation of the muiller reduces the hazard of carbon monoxide gas, by

By the time the gases reach the What I claim is:

1. In a suction muffler a series of spaced tandemwise arranged endwise aligned ejectors, each of said ejectors having a tapered leading portion provided on its outer periphery with inwardly directed inclined passages, open at each end for exhaust gases, the follower end edge of a leading ejector being of frusto-conical contour and overlapping in spaced relation the leading portion of a follower ejector, a housing encompassing in spaced relation and correlating with said ejectors to form an exhaust gas receiving chamber surrounding said ejectors, a nozzle closing the lead ing end of said housing and having its follower end edge of frusto-conical contour surrounding in spaced relation andiopening into the tapered leading portion of the leading ejector, said housing including a rear end wall formed with openings, means correlating with said openings providing an air director discharging in the tapered leading portion of the rear one of said ejectors, and means for supplying exhaust gases to the said chamber.

2. The invention as set forth in claim 1 said housing having the major portion of its length tapered and its remaining portion of uniform diameter arranged rearwardly of the tapered portion, the said means for supplying exhaust to said chamber opening into the housing portion of uniform diameter, each of said ejectors in cluding a tapered follower portion, the taper of the leading portions of the ejectors being greater than the taper of their follower portions, and said ejectors being progressively decreasing in diameter from the rear to the front ejector.

3. In a suction muffler a series of spaced tandemwise arranged endwise aligned ejectors, each of said ejectors having a tapered leading portion provided on its outer periphery with inwardly directed inclined passages, open at each end for exhaust gases, the follower end edge of a leading ejector being of frusto-conical contour and overlapping in spaced relation the leading portion of a follower ejector, a housing encompassing in spaced relation and correlating with said ej ectors to form an exhaust gas receiving chamber surrounding said ejectors, a nozzle closing the leading end of said housing andhaving its follower y end edge of frusto-oonical contour surrounding in spaced relation and opening into the tapered portion of the leading ejector, said housing including a rear end wall formed with openings, means correlating with said openings providing an air director discharging in the tapered leading portion of the rear one of said ejectors, means for supplying exhaust gases to the said chamber, and shiftable means correlating with the housing and common to said ejectors for suspending the leading ejectors in said chamber, for maintaining them in spaced relation with respect to each other and in spaced relation with respect to the body of the housing and for varying space between the ejectors, the rearmost ejector being secured to said rear wall, spaced from the body of the housing and encompassing said airdirector.

'4. The invention as set forth in claim 1 said housing formed of an outer tapered portion and a rear portion of uniform diameter, the said means for supplying exhaust gases to said chamber including a horizontal part and a vertical part, the latter being disposed at right angles to and opening into the housing portion of uniform diameter, each of said ejectors including a tapered follower portion. the taper of the leading portions of the ejectors being greater than their follower portions and said ejectors being tubular and progressively decreasing in diameter from the rear to the front ejector.

5. In a suction muiller a series of spaced tandemwise arranged endwise aligned ejectors, each of said ejectors having a tapered leading portion provided on its outer periphery with inwardly directed inclined passages open at each end for exhaust gases, the follower end edge of a leading ejector being of frusto-conical contour and overlapping in spaced relation the leading portion of a follower ejector, a housing encompassing in spaced relation and correlating with said ejectors to form an exhaust gas receiving chamber surrounding said ejectors, a nozzle closing the leading end of said housing and having its follower end edge of frusto-conical contour surroundin in spaced relation and opening into the tapered portion of the leading ejector, said housing including a rear end wall formed with coaxially arranged circular rows of spaced air intake openings, a set of coaxially arranged forwardly extending frusto-conical members having correlated means forming spiral air passages therebetween leading from the openings of the inner ones of the said rows, the said membersat their rear ends being secured to the forward face of said wall, a frusto-conical shaped member encompassing the outer one of said members and extending forwardly beyond the members of said sets, the outer one of the members of said set and said elongated member having correlated means to form spiral air passages therebetween leading from the outer row of openings, an air discharge member at the leading end of said elongated member, and means for supplying exhaust gases to said chamber.

6. In a suction muiller a series of spaced tandemwise arranged endwise aligned ejectors, each of said ejectors having a tapered leading portion provided on its outer periphery with inwardly directed inclined passages, open at each end for exhaust gases, the follower end edge of a leading ejector being of frusto-conical contour and overlapping in spaced relation the leading portion of ,a follower ejector, a housing encompassing inspaced relation and correlating with said ejectors to form an exhaust gas receiving chamber surrounding said ejectors, a nozzle closing 7 the leading end of said housing and having its follower end edge of frusto-conical contour surrounding in spaced relation and opening into the tapered portion of the leading ejector, said housing including a rear end wall formed with openings, means correlating with said openings providing an air director encompassed by and discharging in the tapered portion of the rear one of said ejectors, means for supplying exhaust ases to the said chamber, and a tail pipe structure extended from the leading end of said nozzle and formed with spaced groups of air intake passages opening into said pipe.

7. In a suction muilier a series of spaced tandemwise arranged endwise aligned ejectors, each of said ejectors having a tapered leading portion provided on its outer periphery with inwardly directed inclined passages, open at each end for exhaust gases, 'the follower end edge of a leading ejector being of frusto-conical contour and overlaping in spaced relation the leading portion of a follower ejector, a housing encompassing in spaced relation and correlating with said ejectors to form an exhaust gas receiving chamber surrounding said ejectors, a nozzle closing the leading end of said housing and having its follower end edge of frusto-conical contour surrounding in spaced relation and opening into the tapered portion of the leading ejector, said housing being formed with coaxially arranged rows of spacedv openings, means within the housing, secured to said rear wall and being so constructed to form spaced air conducting passages, an air receiving chamber and a discharge tube for the air chamber opening into the tapered portion of the rearmost ejector axially of the latter, said air conducting passages leading from said openings to the air receiving chamber, and means for supplying exhaust gases to the exhaust gas receiving chamber.

8. In a suction muiiler a series of spaced tandemwise arranged endwise aligned ejectors, each of said ejectors having a tapered leading portion provided on its outer periphery with inwardly directed inclined passages open at each end for exhaust gases, the follower end edge of a leadingejector being of frusto conical contour and overlapping in spaced relation the leading por tion of a follower ejector, a housing encompassing in spaced relation and correlating with said ejectors to form an exhaust gas receiving chamber surrounding said ejectors, a nozzle closing the structed to form spaced air conducting passages,

an air receiving chamber and a discharge tube for the air chamber opening into the tapered por tion of the rearrnost ejector axially of the latter, saidair conducting passages leading from said openings to the air receiving chamber, and means for supplying exhaust gases to the exhaust gas receiving chamber, the said passages for the err-=- haust gases and the said air conducting passages being oi spiral form.

9. In a suction muiiier a series of spaced tan= ,dernwise endwise aligned ejectors, each oi said ejectors having a tapered leading portion providedon its outer periphery with inwardly directed inclined passages, open at each end for exhaust gases, the follower end edge of a leading ejector being of frusto-conical contour overlapping in spaced relation the leading portion of a follower ejector, a housing encompassing inof the rear one of said ejectors, means for supplying'exhaust gases to the said chamber, and a tail pipe structure from the leading end of said nozzle and formed with spaced groups of air intake passages opening into said pipe, the said passages for the exhaust gases, the said air conducting passages and the said air intake passages being of spiral form.

10. in a suction mufiler a housing having an end wall formed with air intake openings and a leading open end, a nozzle secured in and extended from said open end, a series of spaced endwise aligned overlapping tubular ejectors supported in and disposed relatively to the housing to form an exhaust gas receiving chamber surrounding and common to said ejectors, each of said ejectors having a tapered leading portion formed on its outer periphery with exhaust gas conducting passages open at each end, an exhaust gas conducting pipe opening into said chamber, and means arranged in the rearmost ejector and being formed with spiral air conducting passages correlated with said openings for discharging air into such ejector axially of the latter.

11. In a suction muifiler, a series of tandemwise arranged endwise aligned ejectors having tapered leading portions formed on their outer peripheries with inwardly extending passages for exhaust gases open at each end, the follower end edges of the leading ejectors overlapping in spaced relation the leading portions of the follower ejectors, a housing encompassing in spaced relation and correlating with said ejectors to form an exhaust gas receiving chamber surrounding the ejectors, a nozzle extending from the leading end oi said housing and having its follower end edge surrounding in spaced relation and opening into the tapered portion of the leading ejector, said housing including arear wall formed with openings, means connected to said wall and correlating with said openings provid-- ing air to admix with exhaust gases, said structure including a support formed with air inlet openings, a set of coaxially arranged frustoconical members extended from said support and having correlated means to provide therebetween air conducting passages of spiral form leading from said inlet openings. i 13. In a suction muiiier, a structure for directing air to admix with exhaust gases, said structure including a supportv formed with air inlet openings, a set of coaxially arranged irustoconical members extended from said support having correlated means to provide therebetween air conducting passages of spiral .iorm leading from said inlet openings, the outermost one of said members being of greater length than and forming forwardly of the others of said members an air receiving chamber into which said spiral passages open, and the said outermost one of the said members having its leading end provided with a tubular air discharging member for said chamber. 14. In a suction mufiier, a set of annular tandemwise arranged spaced ejectors each including a forwardly extending inwardly directed tapered leading portion and a follower portion ter-' minating at its leading end into the follower end of the leading portion, said follower portion gradually decreasing in inner and outer diameters from its follower to its leading end, said leading portion being provided in and extended from end to end of its outer periphery with a circumferentially extending row of spaced inwardly directed inclined passages for exhaust gases, said passages being open at each end, the follower end edges of the follower portions of the leading ejectors being of frusto-conical contour and encompassing in spaced relation the leading portions of the follower electors, an annular head having a rear end edge of frustoconical contour encompassing in spaced relation the leading portion of the front ejector of said set, and a housing encompassing in spaced relation said set of electors and said head and connected to the latter, said housing having an intake for exhaust gases arranged relatively to the rear elector of said set.

15. In a suction rnufller, a set of annular tandemwise arranged spaced electors each including a forwardly extending inwardly directed tapered leading portion and a follower portion terminating at its leading and into the follower end of the leading portion, said follower portion gradually decreasing in inner and outer diameters from its follower to its leading end, said leading portion being provided in and extended from end to end of its outer periphery with a circumferentially extending row of spaced inwardly directed inclined passages for exhaust gases, said passages being open at each end, the follower end edges of the follower portionsof the leading electors being of frusto-conical contour and encompassing in spaced relation the leading portions of the follower electors, an annular head having a rear end edge of frusto-conical contour encompassing in spaced relation the leading portion of the front electors of said set, a housing encompassing in spaced relation said set of electors and said head and connected to the latter, said housing having an intake for exhaust gases arranged relatively to the rear ejector of said set, and means for adjusting said electors relative to each other, said means being connected to the electors and to said housing.

16. In a suction muiiler, a set of annular tandemwise arranged spaced electors each including a forwardly extending inwardly directed tapered leading portion and a follower portion terminating at its leading end into the follower end of the leading portion, said follower portion gradually decreasing in inner and outer diameters from itsfollower to its leading end, said leading portion being provided in and extended from end to end of its outer periphery with a circumferentially extending row of spaced inwardly directed inclined passages for exhaust gases, said passages being open at each end, the follower end edges of the follower portions of the leading electors being of frusto-conical contour and encompassing in spaced relation the leading portions of the follower electors, an annular head having a rear end edge of frusto-conical contour encompassing in spaced relation the leading portion of the front ejector of said set, and a housing emcompassing in spaced relation said set of electors and said head and connected to the latter, said housing having an intake for exhaust gases arranged relatively to the rear elector of said set, said housing formed of a rear portion of uniform diameter surrounding in spaced relation therear elector of said set and a portion of gradually decreasing diameter extending forwardly from said housing rear portion and surrounding the other electors of said set and said head.

17. The invention as set forth by claim 14 hav- 

